Monomer Ratio Research Articles

Synthesis and Characterization of Waterborne Sulfonate Polyesters

AbstractWaterborne sulfonate polyesters (WSPs) are prepared by esterification and condensation reaction using 1,4‐cyclohexadimethanol, diethylene glycol, and iso‐phthalic acid as monomers and 5‐sulfoisophthalic acid monosodium salt as hydrophilic monomers. The obtained WSPs are characterized with Fourier transform infrared spectroscopy, 1H NMR, differential scanning calorimetry, thermogravimetric analysis, dynamic light scattering, and water contact angle is also investigated. Their Tg can be adjusted between 30 and 55 °C by changing the ratio of monomers. The WSPs have good thermal stability at 350 °C. The static contact results show that the existence of sulfonic group enhances the hydrophilicity of WSPs. Compared with the waterborne acrylic polyester and polyurethane sold in the market, the prepared WSPs show excellent defoaming performance.

Enhanced photocatalytic performance of PS/F-PANI/PNT films for visible-light-induced hydrogen production

This study aims to develop polystyrene/polyaniline/Pt/N-TiO2 (PS/PANI/PNT) photocatalytic films for hydrogen production under simulated sunlight to improve the efficiency of photocatalyst recycling. The effects of the molar ratio of aniline monomer (AN) to oxidizing reagent (ammonium peroxydisulfate, APS) and the weight ratio of AN to PNT on the conductivity of synthesized nanofiber PANI (F-PANI) materials were investigated. PS/PANI/PNT with F-PANI/PNT were synthesized for photocatalytic hydrogen production. An AN/APS molar ratio of 1:2 in F-PANI/PNT was suitable for AN oxidation. The conductive pathway of PANI chains was enhanced by PNT addition at a AN/PNT weight ratio of 1:0.25, which was favorable for enhancing conductivity, facilitating the faster migration of electron–hole pairs to the photocatalyst surface to improve the hydrogen production rate. The F-PANI/PNT photocatalyst effectively separates its electron–hole pairs and has strong electron reduction and hole oxidation abilities, which is suitable for improving the photocatalytic hydrogen production capacity. The contact angle of PS/F-PANI/PNT-2–0.25 was lower than that of PS/PNT, indicating that the hydrophilicity and active sites of PS/F-PANI/PNT-2–0.25 increased. The optimal photocatalytic hydrogen production of F-PS/PANI/PNT (28,580 μmol h-1 g-1) was reached when the polymerization temperature, AN/APS molar ratio, and AN/PNT weight ratio were 5 °C, 1:2, and 1:0.25, respectively. The PS/F-PANI/PNT film showed excellent recyclability, with comparable photocatalytic activity even after five cycle repetition tests. This approach provides a promising alternative to traditional photocatalytic systems and contribute to a more efficient photocatalyst recycling process.

Modification of hyaluronic acid to enable click chemistry photo-crosslinking of hydrogels with tailorable degradation profiles

Hyaluronic acid (HA) is a naturally occurring mucopolysaccharide that, due to its inherent bioactivity and extracellular matrix-like structure, has the potential to be utilised extensively in tissue engineering. However, this glycosaminoglycan lacks the properties required for cellular adhesion and photo-crosslinking by UV light, which significantly hinders this polymers applicability. This research presents a method for modifying hyaluronic acid via thiolation and methacrylation to generate a novel photo-crosslinkable polymer with improved physicochemical properties, biocompatibility and the potential to customize biodegradability according to the ratio of monomers used. A decrease in stiffness proportional to increasing thiol concentration was observed when testing the compressive strength of hydrogels. Conversely, it was noted that the storage moduli of hydrogels increased proportionally to thiol concentration indicating a greater degree of cross-linking with the addition of thiol. The addition of thiol to HA increased the biocompatibility of the material in both neuronal and glial cell lines and improved the degradability of methacrylated HA. Due to the enhanced physicochemical properties and biocompatibility imparted by the introduction of thiolated HA, this novel hydrogel system could have numerous bioengineering applications.

Antibacterial and pH-sensitive methacrylate poly-L-Arginine/poly (β-amino ester) polymer for soft tissue engineering

During the last decade, pH-sensitive biomaterials containing antibacterial agents have grown exponentially in soft tissue engineering. The aim of this study is to synthesize a biodegradable pH sensitive and antibacterial hydrogel with adjustable mechanical and physical properties for soft tissue engineering. This biodegradable copolymer hydrogel was made of Poly-L-Arginine methacrylate (Poly-L-ArgMA) and different poly (β- amino ester) (PβAE) polymers. PβAE was prepared with four different diacrylate/diamine monomers including; 1.1:1 (PβAE1), 1.5:1 (PβAE1.5), 2:1 (PβAE2), and 3:1 (PβAE3), which was UV cross-linked using dimethoxy phenyl-acetophenone agent. These PβAE were then used for preparation of Poly-L-ArgMA/PβAE polymers and revealed a tunable swelling ratio, depending on the pH conditions. Noticeably, the swelling ratio increased by 1.5 times when the pH decreased from 7.4 to 5.6 in the Poly-L-ArgMA/PβAE1.5 sample. Also, the controllable degradation rate and different mechanical properties were obtained, depending on the PβAE monomer ratio. Noticeably, the tensile strength of the PβAE hydrogel increased from 0.10 ± 0.04 MPa to 2.42 ± 0.3 MPa, when the acrylate/diamine monomer molar ratio increased from 1.1:1 to 3:1. In addition, Poly-L-ArgMA/PβAE samples significantly improved L929 cell viability, attachment and proliferation. Poly-L-ArgMA also enhanced the antibacterial activities of PβAE against both Escherichia coli (~5.1 times) and Staphylococcus aureus (~2.7 times). In summary, the antibacterial and pH-sensitive Poly-L-ArgMA/PβAE1.5 with suitable mechanical, degradation and biological properties could be an appropriate candidate for soft tissue engineering, specifically wound healing applications.Graphical

Preparation and performance study of the self-brittle composite detergent with controllable morphology for radioactive decontamination of surface layer of various materials by RAFT one-pot synthesis

Reversible deactivated radical polymerization (RDRP) has obvious advantages in the synthesis of block copolymers with well-defined structure and composition, but it has some defects in practical applications. An amphiphilic block copolymer (PMAA-co-PTFEMA)-b-PMMA-b-(PMAA-co-PTFEMA) with the self-brittle function was prepared by the reversible addition-fragmentation chain transfer polymerization (RAFT) one-pot method using S, S-dibenzyl trithiocarbonate (DBTTC) as the chain transfer agent, methyl methacrylate (MMA) as the first monomer, methacrylic acid (MAA) as the second monomer, and trifluoroethyl methacrylate (TFEMA) as the modified component. Then it was grafted onto the surface of the modified nano-silica with KH570-modified nano-silica after high-speed shearing, and a self-brittle composite detergent that can be used for radioactive decontamination of surface layers of various materials was prepared by controlling the morphology of the nano-silica. By observing the detergent with different monomer ratios, it can be seen that the control of the self-brittlement morphology of the detergent can be achieved by adjusting the ratio of MMA/MAA, which lays the foundation for future practical applications.

Control of Surface Morphology, Adhesion and Friction of Colloidal Gels with Lamellar Surface Interactions

AbstractDespite recent advances in polyelectrolyte systems, designing responsive hydrogel interfaces to meet application requirements still proves challenging. Here, semicrystalline colloidal gels composed of poly(methacrylamide‐co‐methacrylic acid) are investigated in water with storage moduli in the MPa range. A combination of SEM, X‐ray scattering, and NMR reveals the evolution of the colloidal microstructure, crystallinity, and hydrogen bonding with varying monomer ratio. The gels with the finest colloidal microstructure exhibit the most dissipative rheological behavior and are selected for the study of their interfacial characteristics and underlying interactions. Microstructure stabilization and dynamics results from short‐range (attractive) hydrogen bonding and hydrophobic forces, and long‐range (repulsive) electrostatic interactions—the “SALR” pair potential. Further, the gel's surface exhibits a submicron colloidal topography that greatly determines (colloidal‐like) friction as a result of the viscoelastic deformation of the colloidal network, while electrostatic near‐surface interactions propagate in lamellar adhesion. The dynamic and reversible nature of the involved interactions introduces a stimulus responsive behavior that enables the electrotunability of adhesion and friction. This study advances the knowledge necessary to design complex hydrogel interfaces that enable spatial and dynamic control of surface properties, which is of relevance for applications in biomedical devices, soft tissue design, soft robotics, and other engineered tribosystems.

Effect of Molecular Weight and Chemical Structure of Terminal Groups on the Properties of Porous Hollow Fiber Polysulfone Membranes

For the first time, polysulfones (PSFs) were synthesized with chlorine and hydroxyl terminal groups and studied for the task of producing porous hollow fiber membranes. The synthesis was carried out in dimethylacetamide (DMAc) at various excesses of 2,2-bis(4-hydroxyphenyl)propane (Bisphenol A) and 4,4'-dichlorodiphenylsulfone, as well as at an equimolar ratio of monomers in various aprotic solvents. The synthesized polymers were studied by nuclear magnetic resonance (NMR), differential scanning calorimetry, gel permeation chromatography (GPC), and the coagulation values of 2 wt.% PSF polymer solutions in N-methyl-2-pyrollidone were determined. According to GPC data, PSFs were obtained in a wide range of molecular weights Mw from 22 to 128 kg/mol. NMR analysis confirmed the presence of terminal groups of a certain type in accordance with the use of the corresponding monomer excess in the synthesis process. Based on the obtained results on the dynamic viscosity of dope solutions, promising samples of the synthesized PSF were selected to produce porous hollow fiber membranes. The selected polymers had predominantly -OH terminal groups and their molecular weight was in the range of 55-79 kg/mol. It was found that porous hollow fiber membrane from PSF with Mw 65 kg/mol (synthesized in DMAc with an excess of Bisphenol A 1%) has a high helium permeability of 45 m3/m2∙h∙bar and selectivity α (He/N2) = 2.3. This membrane is a good candidate to be used as a porous support for thin-film composite hollow fiber membrane fabrication.

Efficient synthesis and photocatalytic activity of newly synthesized core-shell nanocomposites

ABSTRACT The current approach represents a synthetic technique for developing novel core-shell nanocomposites (CSNCs) based on titanium dioxide. TiO2@poly(anthranilic acid-co-o-phenylenediamine) (TiO2@PANA-o-PDA) CSNCs were synthesized by applying varied loads of TiO2 and the fivefold molar ratio of the proper monomers via polycondensation. The newly synthesized TiO2@PANA-o-PDA CSNCs were confirmed by different characterizations. The linkage between PANA-o-PDA and TiO2 was observed in the FT-IR spectra. The CSNCs structures have core-shell features possessing sizes 17–27 nm. Under sunlight irradiation, these CSNCs demonstrate significant photocatalytic activity toward MB dye degradation. Appropriate clarifications of the photocatalytic efficiency results were explicated. The PDI, y-intercept, and ζ of a particle were estimated by DLS for the copolymer colloidal system. This protocol manipulates the cheap, essential, as well as beneficial synthetic setup to produce unique CSNCs as novel potential formulations.

Protective effects of melatonin on myocardial microvascular endothelial cell injury under hypertensive state by regulating Mst1

BackgroundThis study explored the protective effects of melatonin on the hypertensive model in myocardial microvascular endothelial cells.MethodsMouse myocardial microvascular endothelial cells were intervened with angiotensin II to establish hypertensive cell model and divided into control, hypertension (HP), hypertension + adenovirus negative control (HP + Ad-NC), hypertension + adenovirus carrying Mst1 (HP + Ad-Mst1), hypertension + melatonin (HP + MT), hypertension + adenovirus negative control + melatonin (HP + Ad-NC + MT), and hypertension + adenovirus carrying Mst1 + melatonin (HP + Ad-Mst1 + MT) groups. Autophagosomes were observed by transmission electron microscope. Mitochondrial membrane potential was detected by JC-1 staining. Apoptosis was detected by flow cytometry. Oxidative stress markers of MDA, SOD and GSH-PX were measured. The expression of LC3 and p62 was detected by immunofluorescence. Expression levels of Mst1, p-Mst1, Beclin1, LC3, and P62 were detected with Western blot.ResultsCompared with the control group, the autophagosomes in HP, HP + Ad-Mst1, and HP + Ad-NC groups were significantly reduced. Compared with HP group, the autophagosomes in HP + Ad-Mst1 group were significantly reduced. The apoptosis of HP + MT group was significantly lower than HP group. Compared with HP + Ad-Mst1 group, the apoptosis of HP + Ad-Mst1 + MT group was significantly reduced. The ratio of JC-1 monomer in HP + MT group was significantly lower than HP group. Compared with HP + Ad-Mst1 group, the mitochondrial membrane potential of HP + Ad-Mst1 + MT group was also significantly reduced. MDA content in HP + MT group was significantly reduced, but SOD and GSH-PX activities were significantly increased. Compared with HP + Ad-Mst1 group, MDA content in HP + Ad-Mst1 + MT group was significantly reduced, whereas SOD and GSH-PX activities were increased significantly. Mst1 and p-Mst1 proteins in HP + MT group were significantly reduced. Compared with HP + Ad-Mst1 group, Mst1 and p-Mst1 in HP + Ad-Mst1 + MT group were reduced. P62 level was significantly decreased, while Beclin1 and LC3II levels were significantly increased. P62 in HP + MT group was significantly reduced, while Beclin1 and LC3II were significantly increased. Compared with HP + Ad-Mst1 group, P62 in HP + Ad-Mst1 + MT group was significantly reduced, but Beclin1 and LC3II were significantly increased.ConclusionMelatonin may inhibit apoptosis, increase mitochondrial membrane potential, and increase autophagy of myocardial microvascular endothelial cells under hypertensive state via inhibiting Mst1 expression, thereby exerting myocardial protective effect.

Synthesis and Plugging Performance of Nano-Micron Polymeric Gel Microsphere Plugging Agents for Oil-Based Drilling Fluids

As shale gas recovery progresses to deep layers, the wellbore instability during drilling in applications of oil-based drilling fluids (OBFs) becomes increasingly severe. This research developed a plugging agent of nano-micron polymeric microspheres based on inverse emulsion polymerization. Through the single-factor analysis with respect to the permeability plugging apparatus (PPA) fluid loss of drilling fluids, the optimal synthesis conditions of polymeric microspheres (AMN) were determined. Specifically, the optimal synthesis conditions are as follows: the monomer ratio of 2-acrylamido-2-methylpropanesulfonic acid (AMPS): Acrylamide (AM): N-vinylpyrrolidone (NVP) were 2:3:5; the total monomer concentration was 30%; the concentrations and HLB values of emulsifier (Span 80: Tween 60) were 10% and 5.1, respectively; the oil-water ratio of the reaction system was 1:1; the cross-linker concentration was 0.4%. The polymeric microsphere (AMN) produced via the optimal synthesis formula had the corresponding functional groups and good thermal stability. The size distribution of AMN ranged mainly from 0.5 to 10 μm. The introduction of AMND in OBFs can increase the viscosity and yield point of oil-based drilling fluids and slightly decrease the demulsification voltage but significantly reduce high temperature and high pressure (HTHP) fluid loss and permeability plugging apparatus (PPA) fluid loss. The OBFs with 3% polymeric microsphere dispersion (AMND) reduced the HTHP and PPA fluid loss by 42% and 50% at 130 °C, respectively. In addition, The AMND maintained good plugging performance at 180 °C. The AMN particles can block leakoff channels of artificial cores, effectively prevent the invasion of oil-based drilling fluids into formations and suppress pressure transfer. OBFs with 3% AMND enabled the corresponding equilibrium pressure to decrease by 69%, compared with that of the OBFs. The polymeric microspheres had a wide particle size distribution. Thus, they can well match leakage channels at various scales and form plugging layers via compression-deformation and packed accumulation, so as to prevent oil-based drilling fluid from invading formations and improve wellbore stability.

Facile construction of irinotecan loaded mesoporous nano-formulation with surface-initiated polymerization to improve stimuli-responsive drug delivery for breast cancer therapy

This work uses rice husk to fabricate mesoporous silica nanoparticles (D-RMN) for breast cancer therapy. The biocompatible dual-responsive (DAN-RMN) was developed by polymerizing acrylic acid (AA) and n-isopropyl acrylamide (NIPAM) on the DV-RMN surface monomeric ratio to increase drug delivery efficiency after vinyl groups were added to the surface of nanoparticles (DAN-RMN). Various analytical and spectroscopical methods characterized the fabricated nanoparticles. Additionally, further encapsulation with SN-38 into the DAN-RMN enhances anticancer efficiency. The in-vitro controlled SN-38 release displayed remarkable temperature and pH response. The MTT assay established the biocompatibility and cytotoxicity of natural sources of silica and DAN-RMN. The fabricated SN-38@DAN-RMN nanoparticles effectively killed the MDA-MB-231 and 4T1 cancerous cells, confirmed by the MTT assay. The IC50 values of SN-38@DAN-RMN in MDA-MB-231 and 4T1 for 1.8 μg/mL and 1.7 μg/mL, respectively. In addition, acridine orange-ethidium bromide (AO-EB) dual staining methods were used to determine morphological changes of cell shrinkage and fragmentation. Nuclear staining methods confirmed the nuclear fragmentation and condensation of the cells. Further, the cell death was examined using dual staining Annexin V-FITC/PI in flow cytometric analyses to assess apoptosis in the MDA-MB-231 and 4T1 cell lines. The apoptotic cell ratio of SN-38@DAN-RMN in MDA-MB-231 and 4T1 for 27.8 and 32.8, respectively. Since there is no drug leakage in the blood while the carrier is in circulation, the DAN-RMN nanocarrier may be used for targeted and stimuli-responsive administration using ultrasound imaging.

Multi-Block Copolymer Membranes Consisting of Sulfonated Poly(p-phenylene) and Naphthalene Containing Poly(arylene Ether Ketone) for Proton Exchange Membrane Water Electrolysis

Glassy hydrocarbon-based membranes are being researched as a replacement for perfluorosulfonic acid (PFSA) membranes in proton exchange membrane water electrolysis (PEMWE). Here, naphthalene containing Poly(arylene Ether Ketone) was introduced into the Poly(p-phenylene)-based multi-block copolymers through Ni(0)-catalyzed coupling reaction to enhance π-π interactions of the naphthalene units. It is discovered that there is an optimum input ratio of the hydrophilic monomer and NBP oligomer for the multi-block copolymers with high ion exchange capacity (IEC) and polymerization yield. With the optimum input ratio, the naphthalene containing copolymer exhibits good hydrogen gas barrier property, chemical stability, and mechanical toughness, even with its high IEC value over 2.4 meq g-1. The membrane shows 3.6 times higher proton selectivity to hydrogen gas than Nafion 212. The PEMWE single cells using the membrane performed better (5.5 A cm-2) than Nafion 212 (4.75 A cm-2) at 1.9 V and 80 °C. These findings suggest that naphthalene containing copolymer membranes are a promising replacement for PFSA membranes in PEMWE.

A carboxylate terpolymer as a scale inhibitor for geothermal hard water in recirculating systems

AbstractThe inhibition efficiency of polycarboxylic acid will decrease due to the weak acidity of carboxyl group in high Ca2+ geothermal circulating water. To solve this problem, we synthesized a novel carboxyl terpolymer (MA‐AEO‐7/SMAS/MA) with adipate polyoxyethylene ether maleate monoester (MA‐AEO‐7), sodium methacrylate sulfonate (SMAS) and maleic acid (MA). Its inhibition efficiency and mechanism were investigated at high Ca2+. The results indicated that the inhibition efficiency of MA‐AEO‐7/SMAS/MA was 96.84% for CaCO3 at the monomeric ratio of 0.5:1:1 and a dosage of 12 mg L−1. The X‐ray diffraction and scanning electron microscope results of CaCO3 scale showed that the presence of MA‐AEO‐7/SMAS/MA converted CaCO3 calcite to vaterite with smaller particle size. The molecular dynamics and density functional theory calculations indicated that the increased solubility of MA‐AEO‐7/SMAS/MA and the carboxylic acidity in MA‐AEO‐7/SMAS/MA enhanced the Ca2+ chelating properties. The electrostatic repulsion between the sulfonic acid groups made MA‐AEO‐7/SMAS/MA exhibit good dispersion properties. These findings explained why the inhibition efficiency of MA‐AEO‐7/SMAS/MA remained above 80% at Ca2+ concentration of 1500 mg L−1, exceeding the 30%–50% of the three commercial scale inhibitors. This study provides practical insight for the development of scale inhibitors suitable for high Ca2+ geothermal circulating water.

Preparation of pH-responsive block copolymers for separation of cephalosporin antibiotics by open-tubular capillary electrochromatography

Stimuli-responsive block copolymers have exhibited their feasibility for drug delivery and analysis of biomolecules. However, study of the electrophoretic behavior of antibiotics by open tubular capillary electrochromatography (OT-CEC) based on smart block copolymers coatings is still a substantial challenge. Herein, we reported an OT-CEC protocol for analysis of cephalosporin antibiotics with pH-responsive block copolymers as coatings. By using the reversible addition-fragmentation chain-transfers radical polymerisation technique, the smart poly(styrene-maleic anhydride-acrylic acid) (P(St-MAn-AA)) was synthesized and subsequently chemical bonded onto the inner walls of amino-grafted capillaries. The pH induced changes in the stretch/curl states of P(St-MAn-AA) chains were used to generate an adjustable hydrophobic/hydrophilic interaction and hydrogen bonds between the polymer coatings and the analytes. The OT-CEC performance was evaluated by varying the monomer ratios, polymer coating amounts and layers, buffer concentrations and pH values. Baseline separation of the three-test antibiotics was achieved at pH 8.0. The proposed OT-CEC technique was further applied to the determination of rat serum antibiotics in the metabolic processes. The present work demonstrates an enhancement in antibiotics separation efficiency, and shows a great potential for the preparation of stimuli-responsive block copolymers coatings and in OT-CEC analysis of real samples in living bio-systems.

Strengthening soft poly(vinyl chloride) plastics via three-arm star copolymeric plasticizers

Besides the good flexibility and extensibility, plasticized soft poly(vinyl chloride) (PVC) possessing the extra characteristics of high modulus, tensile strength and toughness are desired for wider applications. Herein, a series of three-arm star copolymers possessing the hard polylactide (PLA)-rich core and the soft poly(ε-caprolactone)-rich (PCL) shell (S3-PLA-PCL) were prepared, which were used as the plasticizers for the preparation of soft PVCs. The monomer ratio of ε-caprolactone to lactide (LA), the average polymerization degree of LA and the type of LA (racemic or L type) were optimized to achieve the best mechanical performance of soft PVCs. With the similar elongation at break, S3-PLA-PCL plasticized PVC exhibited higher modulus, strength and toughness than PVCs plasticized by the corresponding linear PLA-PCL and other traditional low molar-mass and polymeric plasticizers without hard core. This pointed out the importance of the star topology and the hard PLA-rich core of S3-PLA-PCL in strengthening soft PVCs. The transparency of PVC plasticized by S3-PLA-PCL was similar to the neat PVC and PVCs plasticized by the traditional plasticizers. Migration stability tests demonstrated that S3-PLA-PCL had excellent migration resistance in PVC matrix. Moreover, both PLA and PCL are sustainable, biocompatible and biodegradable, hence, the as-prepared S3-PLA-PCLs can be called as high-performance, green polymeric plasticizers for PVC plastics.

Preparation of high‐strength, high‐modulus PVA fiber by synthesis of syndiotacticity‐rich high molecular weight PVA polymers with VAc and VBz via emulsifier‐free emulsion polymerization

AbstractDifferent vinyl acetate (VAc) and vinyl benzoate (VBz) monomer ratios have been chosen as monomers to create high polymerization degree (Pn) and high syndiotacticity‐diad content (S‐diad) poly(vinyl alcohol) (PVA) polymers via emulsifier‐free polymerization in order to address the problem of limited mechanical capabilities of PVA fibers prepared with low Pn and low S‐diad polymer. The variations in hydrogen bonding, Pn, S‐diad, and viscosity of different PVA polymers were investigated and evaluated using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, gel permeation chromatography, and a viscosity tester. Moreover, various PVA fibers with high strength and modulus have been manufactured using a synthetic polymer as the raw material for dry‐wet spinning. The effect of Pn and S‐diad on the mechanical and thermal characteristics of PVA fibers is evaluated using a variety of characterization techniques, such as the scanning electron microscope, differential scanning calorimetry, thermogravimetric analyzer, X‐ray diffraction, and tensile tester. As the ratio of VBz monomer increased, the results suggested that VBz may have a considerable impact on the Pn and S‐diad of PVA polymers, the OH vibration absorption peak reduced from 3491 to 3442 cm−1; the Pn increased from 2112 to 17,704; and the S‐diad rose from 51.2% to 60.1%. In addition to the fact that Pn and S‐diad significantly increased the fibers' strength and modulus, the crystallinity increased from 41.8% to 51.7%, and the orientation degree rose from 87.5% to 91.7%, as Pn and S‐diad increased; the tensile strength and highest elastic modulus increased from 9.71 ± 0.3 cN/dtex to 12.74 ± 0.5 cN/dtex (increased of 31.2%) and 264.52 ± 9.3 cN/dtex to 338.41 ± 8.6 cN/dtex (increased of 27.9%); the elongation at break decreased from 5.63 ± 0.3% to 2.92 ± 0.2%.

Synthesis, Characterization and Application of a MIP-polyHIPE for Selective Extraction of Angiotensin II Receptor Antagonists Residues in Natural Waters.

Polymers via high internal phase emulsion (polyHIPEs) were molecularly imprinted with Irbesartan, an antihypertensive drug belonging to the class of angiotensin II receptor antagonists (sartan drugs), chosen for the proof-of-concept extraction of hazardous emerging contaminants from water. Different analyte-functional monomer molar ratios (1:100, 1:30 and 1:15) were investigated, and the MIP polyHIPEs have been characterized, parallel to the not imprinted polymer (NIP), by batch sorption experiments. The material with the highest template-functional monomer ratio was the best for Irbesartan removal, showing a sorption capacity fivefold higher than the NIP. Regarding the adsorption kinetics, the analyte-sorbent equilibrium was reached after about 3 h, and the film diffusion model best fitted the kinetic profile. Selectivity was further demonstrated by testing Losartan, another sartan drug, observing a fourfold lower sorption capacity, but still higher than that of NIP. The polymers were also synthesized in cartridges for solid-phase extraction (SPE), which was helpful for evaluating the breakthrough curves and performing pre-concentrations. These have been done in tap and river water samples (100-250 mL, 15-500 µg L-1 Irbesartan), obtaining quantitative sorption/desorption on the MIP-polyHIPE (RSD < 14%, n = 3). The NIP provided a recovery of just around 30%, evidence of partial uptake of the target from water.

Large and Tunable Ranking Shift in Triboelectric Series of Polymers by Introducing Phthalazinone Moieties.

Regulating the ranking of polymer in triboelectric series over a wide range is of great help for material's selection of triboelectric nanogenerators (TENGs). Herein, fluorinated poly(phthalazinone ether)s (FPPEs) with tunable molecular structure and aggregate structure are synthesized by co-polycondensation, while the large positive ranking shift in the triboelectric series can be achieved by introducing phthalazinone moieties with strong electron donating capability. FPPE-5, which includes abundant phthalazinone moieties, is more positive than all of the previously reported triboelectric polymers. Hence, the regulating range of FPPEs in this work updates a new record in triboelectric series, which is wider than that of previous works. A peculiar crystallization behavior, capable of trapping and storing more electrons, has been observed in FPPE-2with 25% phthalazinone moieties. Correspondingly, FPPE-2is more negative than FPPE-1without a phthalazinone moiety, which is an unexpected shift against the common changing tendency in triboelectric series. With FPPEs films as the probing material, a tactile TENG sensor is applied to enable material identification via electrical signal polarity. Hence, this study demonstrates a strategy to regulate the series of triboelectric polymers by copolymerization using monomers with distinct electrification capabilities, where both the monomer ratio and the peculiar nonlinear behavior can control triboelectric performance.

Thermoresponsive Shape-Memory Biobased Photopolymers of Tetrahydrofurfuryl Acrylate and Tridecyl Methacrylate.

A series of thermoresponsive shape-memory photopolymers have been synthesized from the mixtures of two biobased monomers, tetrahydrofurfuryl acrylate and tridecyl methacrylate, with the addition of a small amount of 1,3-benzendithiol (molar ratio of monomers 0-10:0.5:0.03, respectively). Ethyl (2,4,6 trimethylbenzoyl) phenylphosphinate was used as photoinitiator. The calculated biorenewable carbon content of these photopolymers was in the range of (63.7-74.9)%. The increase in tetrahydrofurfuryl acrylate content in the photocurable resins resulted in a higher rate of photocuring, increased rigidity, as well as mechanical and thermal characteristics of the obtained polymers. All photopolymer samples showed thermoresponsive shape-memory behavior when reaching their glass transition temperature. The developed biobased photopolymers can replace petroleum-derived thermoresponsive shape-memory polymer analogues in a wide range of applications.

Preparation of phthalonitrile resins containing siloxane linkages with improved processability

To improve the processability of biphenyl phthalonitrile resin, a flexible siloxane structure was introduced into the phthalonitrile monomer through molecular design, which was then blended with a biphenyl monomer to prepare phthalonitrile alloy resins. When the ratio of phthalonitrile monomer containing flexible siloxane to biphenyl phthalonitrile monomer was 1:1, the processing window widened from 58 to 110°C, as compared to that of biphenyl phthalonitrile. Due to the introduction of the biphenyl structure into the phthalonitrile alloy resins, the initial decomposition temperature of the silicon-containing phthalonitrile resin increased from 385 to 516°C. More importantly, the phthalonitrile alloy resin exhibited a high bending strength (66 MPa) and bending modulus (3762 MPa), indicating that it could be potentially applied as high temperature structural composite matrices. Furthermore, it provides a new strategy for processing phthalonitrile resins with a high melting point and narrow processing window.